This invention generally relates to perfusion type dilatation catheters for use in percutaneous transluminal coronary angioplasty (PTCA).
In typical PTCA procedures a balloon dilatation catheter is advanced over a guidewire to a desired location within the patient's coronary anatomy where the balloon of the dilatation catheter is properly positioned within the stenosis to be dilated. The balloon is then inflated to a predetermined size with radiopaque liquid at relatively high pressures (e.g. generally 4-12 atmospheres) to dilate the stenosed region of the diseased artery. One or more inflations may be needed to effectively dilate the stenosis. After the dilatation of the first stenosis the catheter may be advanced further into the patient's coronary anatomy to dilate additional stenoses.
A high number of angioplasty procedures result in a dissected arterial lining which can cause an acute closure of the arterial passageway. In the latter instances a perfusion device must be advanced over the in-place guidewire to ensure adequate blood blow distal to the dissected lining until the lining can be resecured to the artery wall, coronary or a by-pass procedure commenced. Preferably, a dilatation balloon catheter with perfusion capabilities is advanced over the in-place guidewire until the balloon crosses the dissection and the balloon is inflated to press the dissected lining back into place against the arterial wall. With the balloon inflated, blood is caused to pass through a perfusion passageway through the balloon to discharge the blood distal to the catheter. The balloon is maintained in an inflated condition for sufficiently long periods of time, e.g. from about 0.5 to about 6 hours, for the natural healing process to resecure the dissected lining to the arterial wall.
Balloon catheters with perfusion capabilities have been available from Advanced Cardiovascular Systems, Inc. for a number of years, including the RX Perfusion Coronary Dilatation Catheter and the Lifestream Dilation Catheter which has met with much commercial success. Such catheters are described in U.S. Pat. No. 5,496,275 (Sirhan et al) and U.S. application Ser. No. 08/183,574, filed on Jan. 18, 1994 which are incorporated herein in their entirety. The perfusion catheters presently on the market are predominantly rapid exchange type dilatation catheters due to the frequent need to advance a perfusion catheter over an in-place guidewire when an acute occlusion occurs after the original dilatation catheter has been deflated and withdrawn from the stenotic region.